1. Field of the Invention
The present invention relates to mobile communications systems and more particularly to a mobile communications system which includes a redundant register network for automatically controlling and supervising units in a switching system.
2. Description of the Related Art
Mobile communications systems include a switching unit which is responsible for performing call processing and subscriber related functions. The switching unit includes various units for storing and processing subscriber information. For example, the switching unit includes a Home Location Register (HLR) which is a database for storage and management of subscriptions. The HRL stores permanent data for subscribers, including a service profile, location information and activity status for each subscriber. Specifically, HLR subscriber information includes a International Mobile Subscriber Identity (IMSI), service subscription information, location information which includes the identity of a currently serving Visitor Location Register (VLR) to enable routing of mobile-terminated calls, service restrictions and supplementary services information. In addition to the HRL, the switching system includes an authentication center (AUC) which is a unit that provides authentication and encryption parameters that verify the user's identity and ensure the confidentiality of each call. The switching system also includes an equipment identity register (EIR) which is a database that includes information about the identity of mobile equipment to prevent calls from stolen, unauthorized or defective mobile stations.
Traditional communications network design is based on the utilization of a single Home Location Register (HLR) for each network. However, growth considerations and the creation of multi-vendor networks have prompted carriers to implement multiple HLR topologies. During operation of the communication system, the HLR, AUC, and/or EIR may become dysfunctional. When the one of these units goes out of order, current communications systems cannot automatically detect the out-of order status. As such, there is no way to automatically control and supervise HLRs AUCs and/or EIRs in a multi-vendor redundancy solution.